In a large skillet, heat the olive oil over medium heat.
Add the finely chopped onion and sauté for about 5-7 minutes until translucent and slightly golden.
Stir in the chopped garlic and red pepper flakes, cooking for 1-2 minutes.
Pour in the whole peeled San Marzano tomatoes and break them up with a spoon.
Add sea salt and cane sugar, then bring to a gentle simmer.
Allow the sauce to cook uncovered for about 20-30 minutes.
If desired, use an immersion blender for a smoother sauce.
Taste and adjust seasoning if necessary, then serve over pasta or use as a base for other dishes.
